---
title: "What Is Email Warmup? Definition for Cold Email Senders | ONEGTMLAB"
description: "Email warmup is the practice of gradually raising sending volume from a new mailbox or domain to build sender reputation for cold email."
canonical: https://www.onegtmlab.dev/glossary/email-warmup
---

# What Is Email Warmup? Definition for Cold Email Senders | ONEGTMLAB

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GTM Glossary

# Email Warmup

Email warmup is the practice of gradually increasing how much email a new mailbox or domain sends, so mailbox providers can build a sending reputation for it before larger campaigns begin.

Also called: email warm-up, inbox warmup, domain warmup

## Why it matters

A brand new domain or mailbox has no sending history, and a sudden burst of messages from it can look like spam behavior to mailbox providers. Warming up means starting at a low volume and raising it step by step while watching bounces, spam complaints and replies. Teams usually do this after setting up SPF, DKIM and DMARC on the domain.

Warmup can be manual, by sending real conversations to known contacts, or automated, through warmup tools that exchange messages among a network of inboxes and mark them as important. Warmup prepares reputation but cannot fix poor targeting: a warmed mailbox that sends to unverified lists or irrelevant prospects still loses reputation. It is one part of email deliverability, not a substitute for it.

## Example

A company buys two new domains for outbound and creates three mailboxes on each. At first, each mailbox sends a small number of messages to colleagues and partners who reply, and an automated warmup tool adds more exchanges. The team raises volume gradually, checks that messages are landing in inboxes, and only then adds the mailboxes to its cold email sequences.

## Related terms

-   [Email Deliverability](/glossary/email-deliverability)
-   [Cold Email](/glossary/cold-email)
-   [SPF Record](/glossary/spf-record)
-   [DKIM](/glossary/dkim)
-   [DMARC](/glossary/dmarc)

## Related service

[GTM Engineering Signal-led outbound systems that enrich, score, sequence and sync to your CRM.](/ai-gtm-engineering)

## Related playbook

-   [Cold Email Playbook Domains, a verified list, a mail gateway gate, final-text copy and launch checks, in that order.](/growth-playbooks/cold-email)

[← All GTM terms, A to Z](/glossary)

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